Are you adamant about getting acroread? There are other PDF readers that are better in any number of ways. I use Zathura with zathura-pdf-poppler, but there are several other good ones. _________________Gentoo StudioGentoo Studio in open beta. Feedback wanted.

I think this has to do with the letters being uppercase and the phase helper somehow not able to make them lowercase with the above code; however, the same code is present in unpacker.eclass as well as a preliminary check where it actually does evaluate it properly. There is a subtle difference, the above code uses LC_ALL=C whereas unpacker.eclass does not; the LC_ALL=C causes the above code to fail. You will want to file a bug against sys-apps/portage at https://bugs.gentoo.org to fix that; there's a small chance they are right about this, in which case unpacker.eclass must be fixed to match it and then the actual bug would be in tr which is from sys-apps/coreutils. But well, best to start by making the Portage maintainers aware and have them look into this to determine where the issue might lie.